Apparatus for heating feed water for a steam boiler



June 7, 1932. HAGA 1,861,660

APPARATUS FOR HEATING FEED WATER FOR A STEAM BOILER Filed July 27, 1926 Fig 1- INVENTOR. 6- .Haga.

BY WWW A TTORNEY5.

Patented June 7, 1932 UNITED STATES matte PAr FEE ii SOJ'IRO HAGA, F TOKYO, JAPAN Application filed July 27, 1926, Serial No. 125,279, and in Japan December 23, 1925.

This invention relates to an apparatus for pre-heating feed water for a steam boiler, in which heat contained in Waste gases from boiler furnace is utilized, and its object is to provide an apparatus for pre-heating feed water for steam boiler whereby the greatest possible quantity of heat contained in waste gases from the boiler furnace may be utilized.

3.0 The invention consists of means to main tain such a pressure in a feed water heater disposed in the off-take fiue to a boiler that the waste gases passing through the heater will cause the water substantially to boil 1 and means to cause the heat absorbed from the waste gases to be uniformly distributed through the water contained by the heater to ensure much better effect than feed heaters heretofore in use.

My invention will be better understood from the accompanying drawing, in which:

Fig. 1 is a plan view.

Fig. 2 is a side View.

Referring to the drawing I show a vessel 1 disposed in a suitable position in the conduit or passage of waste gases from the boiler furnace so that the feed water passing through the same may be heated by the waste gases. The vessel may be of any suitable form but is preferably constructed as shown, having a number of tubes 2 with their open ends fixed to the end-plates, and by providing a number of agitators 3 by which better circulation can be obtained and thereby the feed water will be thoroughly heated. An automatic pressure regulating mechanism is also provided to maintain in the vessel a certain definite pressure under which the feed water in the vessel is able to change into vapour at that temperature. Any suitable device may be employed for this purpose, but preferably a cylinder 4 is employed fixed upon the top of the vessel 1; the cylinder contains a piston 5 subjected to the tension of a spiral spring 6. The force of piston is so adjusted by a counter weight 7 as to remain inoperative until the predetermined pressure is reached. The piston 5 is provided with a rod 8 having teeth which engage to a pinion 9 and.

in turn to another pinion 10 fixed on the stem of a discharge cock 11 in a discharge pipe 12, p from which the excess of steamis discharged. Moreover, the piston rod 8 is arranged to control the rotation of the shafts 13, 13 which actuate the dampers 14, 14 disposed at the rear ends of waste gas passages 15, 15 between the side walls of the waste gas conduit and the vessel through the discharge cock 11, the discharge pipe 12, and any suitable means, for example, a cylinder 16 containing a spring controlled piston 17 with a rod 18, a lever 19, a rack 20, sector wheels 21, 21 and pinions 22, 22 fixed on the shafts 13, 13 respectively. The inlet and outlet pipes of the feed water are shown at 23 and 24 respectively.

In operation, when the pressure in the vessel 1 surpasses the predetermined pressure, it may be automatically lowered by opening the cook 11 and discharging the excess of steam through the discharge pipes 12 and 26, the piston 17 being moved forward, and at the same time the generation of steam may be automatically reduced by opening the dampers 14, 14 causing the waste gases to pass the side passages 15, 15 so as to diminish the quantity of gas which passes through tubes 2 of the vessel. It is important that the pressure in the vessel should be kept much lower than the boiler pressure. Also the pressure in the vessel may be either at or below the atmospheric pressure so as to absorb a maximum of heat from the gases. Where the pressure is below atmosphere any suit-able means, for example, vacuum pump 25 must be employed.

I do not wish to be restricted to the specified arrangement herein set forth, as various modifications thereof may be made without departing from the spirit and scope of my invention. I desire, therefore, that only such limitation shall be imposed as indicated in the appended claim.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is An apparatus for heating feed water for steam boiler, comprising a vessel having a number of fire tubes adapted to be disposed inc in the off-take flue to a boiler, pressure regulating means for maintaining such a pressure in the vessel that the waste gases passing through the vessel will cause the water substantially to boil and stirring means to cause the heat absorbed from the waste gases to be uniformly distributed through the water contained by the. vessel, said means comprising a spring-actuated piston opposing the steam pressure in the vessel, a steam discharge conduit from the vessel,- a vaLvesnor mally closing the conduit, gearing between said valve and said piston, a damper in the waste gas passage and a second piston in said conduit having gearing connection with the damper.

In testimony whereof I aifix my signature.

SOJIRO HAGA. 

